Maintain. Ance.
Main-tain. A verb. To keep things working and in order.
Main-tain-ance. Not a word. Wait, what?
Main-tain-ance. NO!
Main-ten-ance. A noun. The process of maintaining.
WHY, ENGLISH? WHY? Why do you have to be so cruel? I understand irregular verbs and plurals, but what were you smoking when you did this? Since when does tain become 10?
You can't complain about this anymore. It's perfect!